1. Field of the Invention
The present invention relates to devices for deflecting and focusing a beam of particles for undertaking a selected operation on a workpiece, and in particular to a method and apparatus for focusing and deflecting a beam of neutral particles employing a beam deflection lens for variably shaping the cross-section of the beam.
2. Description of the Prior Art
The manufacture of increasingly smaller electronic modules and circuits and other components having small structural dimensions requires manufacturing tools capable of accurate positioning within the confines of such small dimensions. For example, integrated micro-electronic semiconductor modules and semiconductor circuits must be structurally doped. In the manufacture of other microstructures, particles must be implanted in or applied to an object workpiece, such as a substrate. Such is necessary, for example, in undertaking surface processing or upgrading wherein, because of the scarcity of raw materials and rising raw material costs, only essential locations on the workpiece are processed or upgraded, such as the location of electrical contacts, rather than indiscriminately applying the raw materials to a much broader area of the surface of the workpiece.
Lithographic methods employing light, electron beams and X rays are conventional means for doping micro-electronic components. Lithography with ion beams, wherein patterns of masks are projected onto lacquer, thereby inscribing the lacquer, is still in its infancy. Research has just begun with directing ion beam implantation inscription into a semiconductor wafer, as described in an article by R. L. Seliger et al, J. Vac. Sci. Tech. 16, 1979, p. 1610. This is because suitable sources with high intensity have only recently become available, such as liquid metal ion sources, see the article by L. W. Swanson et al in the same publication at p. 1864. Due to the coulomb interaction at high beam currents, causing an energy spread and a beam spread, high throughput of microstructures has not been achieved, nor is the accuracy and reliability of the small dimensions of the structures to be generated such as, for example, semiconductor elements, been achieved with conventional electron beam and ion beam inscription.